1. Field of the Invention
This invention generally relates to a group-separation device and method for particles based on their magnetic susceptibilities, and more particularly to a column and method for group-separating particles contained in a suspension in accordance with their magnetic susceptibility by using a magnetic chromatography technique with a high gradient magnetic field. This technique is useful in various modern industries for, for example, separation of harmful materials or concentration of materials.
2. Description of Related Art
One of the conventional method for separating particles in a suspension is High Gradient Magnetic Separation (HGMS). This type of magnetic separation utilizes a magnetic force as a pure physical force without a chemical reaction, and therefore has following advantages;
(i) It enables a high speed separation of A large quantity of suspension without using chemicals, and PA1 (ii) It allows the separation system to be repeatedly used without delivering secondary waste since the magnetic force is eliminated simply by cutting off the magnetic field.
Because of the above characteristics, this technique attracts a great deal of attention as a practical technique for the separation of harmful materials or a concentration of materials.
A more advanced HGMS technique which has been studied recently is to provide a magnetic filter comprising ferromagnetic narrow wires in a strong magnetic field generated by a super conductive electro-magnet, and to make a suspension flow through the filter and separate a group of particles by adsorbing them onto the filter material.
Thus, this type of magnetic separation is a solid separating method by adsorbing particles contained in the suspension onto the magnetic filter. A drawback of this method is that it is difficult to adsorb particles having a very small diameter due to competition between the magnetic force and the flowing force. The marginal diameter of adsorbed particles depends on the magnetic susceptibility and the diameter of the particles, and is approximately 10.sup.-7 m for a paramagnetic particles and 10.sup.-8 m for a ferromagnetic particles.